Hepatitis B (HB) and hepatitis C (HC) are two of the most widespread infections worldwide caused by the blood-borne HB virus (HBV) and HC virus (HCV), respectively. About 240 million and 150 million people suffer from chronic HB (CHB) and chronic HC (CHC), respectively while about 780,000 and 350,000-500,000 people die each year due to the consequence of HB and HC, respectively. In highly endemic countries, co-infection of HBV and HCV is also common. HB and HC are also important hazards for healthcare workers and for patients needing transfusion or organ transplant as CHB and CHC are asymptomatic and patients and blood/tissue donors may have HB or HC without knowing it, posing risks to healthcare workers and patients needing transfusion or tissue transplant. Currently HB and HC are diagnosed with two separate sets of tests which can detect HB and HC only weeks or months after the initial infection. Quantitative PCR (qPCR) could detect both HB and HC within the first week of infection but they are expensive not suitable for use in low-resource countries where HB and HC are endemic. They are also two tests, adding up the cost. The goal of the proposed study is to develop a low-cost, rapid, easy-to-use, multiplex, and accurate serum test to detect both HBV DNA and HCV RNA in one test to diagnose HB and HC at point of care, in low-resource HB and HC endemic countries, and to screen for blood and organ supplies. (PbMg1/3Nb2/3O3)0.65(PbTiO3)0.35 (PMN-PT) piezoelectric plate sensor (PEPS) is a new sensor that uses relative resonance frequency shift, ?f/f to detect binding of a target to the receptor on the PEPS surface. Unique to PMN-PT PEPS is that the detection ?f/f is enhanced by 1000 times due to the unique polarization switching mechanism within the PMN- PT layer. As a result, PEPS has demonstrated sensitivity similar to PCR in DNA detection but without the need of DNA extraction and DNA amplification. Lenima Field Diagnostics will develop a 3-PEPS array with one PEPS detecting HBV DNA, a second PEPS detecting HCV RNA, a third PEPS serving as a negative control. Preliminary results indicate 100 viruses/ml analytical sensitivity fr PEPS HBV DNA detection of HBV spiked in serum as similar to the 115 viruses/ml sensitivity of qPCR. Using a similar strategy, PEPS has demonstrated 95% sensitivity and 95% specificity in a separate study of Clostridium difficile toxin B gene detection in 40 patients' stools. It is expected that we will successfully develop the multiplexed PEPS HBV and HCV test to achieve a milestone of >90% sensitivity and >90% specificity. In phase II, we will develop the clinical prototype that includes a portable detection system and disposable array PEPS for patient sample tests towards FDA approval.